Slow Breathing Exercise with Multimodal Virtual Reality: A Feasibility Study.

Many studies have shown that slow breathing training is beneficial for human health. However, several factors might discourage beginners from continuing their training. For example, a long training period is generally required for benefit realization, and there is no real-time feedback to trainees to adjust their breathing control strategy. To raise the user's interest in breathing exercise training, a virtual reality system with multimodal biofeedback is proposed in this work. In our system, a realistic human model of the trainee is provided in virtual reality (VR). At the same time, abdominal movements are sensed, and the breathing rate can be visualized. Being aware of the breathing rate, the trainee can regulate his or her breathing to achieve a slower breathing rate. An additional source of tactile feedback is combined with visual feedback to provide a more immersive experience for the trainees. Finally, the user's satisfaction with the proposed system is reported through questionnaires. Most of the users find it enjoyable to use such a system for mediation training.

[Design of portable blood pressure depressor based on slow breathing training].

Clinical studies had demonstrated that slow breathing could lower blood pressure significantly. Based on this knowledge, a portable blood pressure depressor was designed in this study. The device used a miniature variable distance capacitive sensor to collect respiratory signal, an STM32 as the main control chip, a WT588D voice chip to generate voice and music and guide slow breathing, and a 3.5-inch color screen to display breathing state and provide guidance. For patients with difficulty in adapting themselves to the slow breathing training, an intelligent guiding breathing algorithm based on feedback regulation mechanism was proposed to train patients to breathe slowly. Ten volunteers with hypertension were recruited and then trained to breathe slowly, accumulating up to 100 times using this device. The results showed that breath rate of the volunteers decreased from 15.16±0.92 times per minute to 9.40±0.29 times per minute, and meanwhile, time length of breath rate less than 8 times per minute in the proportion of total treatment time increased from 0.079±0.017 to 0.392±0.019 as the training times increased. In a conclusion, the proposed blood pressure depressor worked effectively in guiding slow breathing training.

Blood pressure changes in patients with chronic heart failure undergoing slow breathing training.

BACKGROUND: Slow breathing training (SBT) has been proposed as a new non-pharmacological treatment able to induce favorable effects in patients with chronic heart failure (CHF). However, no information is available regarding its effects on orthostatic blood pressure (BP) changes in these patients, an issue of practical relevance given the reported BP-lowering effect of SBT. The aim of this study is to evaluate the influence of SBT on BP and whether SBT induces orthostatic hypotension (OH) or changes in quality of life (QoL) in CHF patients. METHODS: The analysis was performed as part of an ongoing crossover open trial aimed at assessing the clinical effectiveness of SBT in treated patients with CHF. The patients underwent 10-12 weeks of SBT with the RESPeRATE device and 10-12 week follow-up under usual care. Patients were randomly divided into two groups: group I began with SBT, followed by usual care; group II began with usual care, followed by SBT. Patients undergoing SBT were asked to perform each day two separate 15 min sessions of device-guided SBT at a breathing frequency of 6 breaths/min. In all patients, before the enrollment and after each study phase, clinical data collection and BP measurements in sitting, supine and standing position were performed. OH was defined as a decrease of ≥ 20 mmHg in systolic blood pressure (SBP) or ≥ 10 mmHg in diastolic blood pressure (DBP) within 3 min of standing. QoL was assessed three times at the beginning, and after each phase of the study by the Minnesota Living with Heart Failure (MLHF) questionnaire. RESULTS: Forty patients (two equal groups) completed the study, with the following baseline characteristics: 32 males/eight females, age 63.3 ± 13.4 years, 25 with ischemic CHF, 37 in New York Heart Association class II and three in class III, left ventricular ejection fraction 30.8 ± 6.7%, mean BP 138.7 ± 16.5/83.1 ± 11.5 mmHg, 23 with arterial hypertension and four with a history of stroke. There were no significant differences between the groups in clinical characteristics, SBP and DBP at rest, while seated and before and after standing up. OH prevalence was low and did not change during the study (10% vs 10%). No significant difference in average SBP and DBP changes secondary to body position were found when comparing the two study phases. Decrease in MLHF score was observed in group I during SBT (p = 0.002), but not in group II. CONCLUSIONS: Our data indicate that SBT is safe, does not affect the prevalence of OH in CHF patients and shows a non-significant tendency to improve QoL. These results should be confirmed in a larger sample of patients to support the safety of SBT and its possible benefits as a novel component of cardiorespiratory rehabilitation programs in CHF.

Effects of slow breathing training on hemodynamic changes, cardiac autonomic function and neuroendocrine response in people with high blood pressure: A randomized control trial.

BACKGROUND: High blood pressure (BP) is a non-communicable disease that is a risk factor for cardiovascular disease and is the leading cause of mortality and morbidity worldwide. High BP can be managed by both pharmacological and non-pharmacological interventions. Non-pharmacological treatment, such as slow-breathing training (SBT), has been shown to reduce BP. However, there are few studies on the effect of SBT on both cardiac activation and oxidative stress in people with high BP. OBJECTIVES: To explore the effect of SBT on cardiac autonomic function (i.e., heart rate variability: HRV) and neuroendocrine response (i.e., salivary cortisol). METHODS: One hundred people (including 89 women) with high BP were randomly assigned to either a control (n = 50) or intervention group (n = 50). The intervention program was conducted for 30 min per day, for 5 days per week, for 4 weeks, with a total of 20 sessions of the SBT at the rate of 10 times per minute, whereas the control group was required to continue with their daily routine. HRV, BP, and salivary cortisol were measured before and after the intervention program. A two-way mixed ANOVA was performed for within-group and between-group comparisons over time. RESULTS: Of the 100 participants, 71 individuals completed the study. The participants in the intervention group had a lower BP and salivary cortisol levels compared to those in the control group (p < .05). Further, those participants showed an increase in the standard deviation of normal R-R intervals after the 4-week intervention program (p < .05). CONCLUSION: This study provided evidence demonstrating the effect of SBT on cardiac autonomic and stress reactivity, which has important implications for health promotion in people with high BP. CLINICAL TRIAL REGISTRATION NUMBER: TCTR20180302008.